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A super‐condensed TLM node for modelling inhomogeneous anisotropic media on an arbitrarily graded mesh without using stubs is developed. It requires less storage, computationally is more efficient and can operate on a higher time step than existing TLM nodes. Complete derivation, implementation and validation of the new node are presented in the paper.

Due to land resource scarcity, sustainable urban development in high-density cities has long been challenging. As such, many cities are formulating plans to “dig deep”, resulting in more citizens working and/or staying underground for longer periods of time. However, owing to the particularities of underground space, the factors involved in the creation of a healthy environment are different from those involved in aboveground developments. This study thus aims to investigate the influences of various underground environment factors on users' health through a holistic approach.

To achieve this aim, 12 underground sites and 12 corresponding aboveground sites are selected for a large-scale questionnaire survey, resulting in 651 survey samples. The survey covers post-occupancy evaluation of health (physical and psychosocial), underground environmental quality (visual, thermal, acoustic comfort, indoor air quality and ventilation), space design and greenery. Independent-sample T-test, Pearson correlation, multiple regression modelling and structural equation modelling are used to investigate whether significant differences exist between health of underground and aboveground users, and to develop an underground environment-health model for unveiling the significant associations between underground environment factors and users' health. To cross validate the results, an objective field measurement study is further conducted on six underground sites. The objective measurement results are used to cross validate the survey results.

The questionnaire results provide the following evidence: (1) health of underground users is significantly poorer than that of their aboveground counterparts; (2) underground development users' health is significantly affected by space design, greenery and environmental quality in terms of thermal comfort, indoor air quality, ventilation and acoustic comfort but not visual comfort; and (3) amongst the various identified factors, space design has the strongest predicting effects on human health. The field study echoes the survey findings and further unveils the relationships between different environmental factors and human health.

The results shed light on the importance of distinguishing between underground developments and aboveground ones in various guidelines and standards, especially those related to space management.

A technique for studying the propagation of surges on lines in the presence of corona and a lossy earth is presented. Each line section is modelled by lumped circuit components representing corona and earth effects. The component values are readily obtained from theoretical and experimental investigations. The circuit is solved in the time domain using transmission line modelling (TLM). The results show good agreement with other experimental and theoretical investigations.

Transmission line modelling is a technique that can be applied to the analysis and design of electromagnetic devices. Developments to the method are described which improve its efficiency and flexibility.

The goal of this paper is twofold: to assess the influence of specific corporate and market features on automobiles and parts sector's profitability in Euro area and to identify this particular sector's optimum debt level.

For the paper's purposes, the authors applied a panel data analysis on an annual basis for the period 2005–2017.

There is a strong statistical significance of debt ratio, growth domestic product per capita growth, E.C.'s economic sentiment index (ESI), the European Central Bank key interest rate and the Euro area crisis on sector's profitability, while weak statistical significance appears to emerge for the firm's size. Moreover, the authors find average 14.4% profitability for the entire sector of the Euro area, without significant fluctuations among firms and/or during the examined time period. Another interesting finding of this study is that results are consistent with the theory of Modigliani Miller that financial leverage at a “low” level is beneficial for the firm, but beyond a turning point, it becomes counterproductive. This turning point for the automobiles and parts sector in Euro area has been computed at 47.3%.

The paper focuses on issues of profitability, capital structure and optimal debt ratio of an important sector of the economy, the automotive sector. As regards the Euro area automotive sector, it is a dynamic sector with a significant multiplier effect for the European economy as it is strongly correlated with other industrial sectors as chemicals, steel, textiles, information technology and so forth, having an outstanding multiplier effect on the economy.

Coopetition (simultaneous cooperation and competition of actors) is still a relatively new concept in business, management, and tourism. However, several coopetition studies have focused on tourism and tourism destinations. Also, compilation literature reviews of tourism and tourism destinations have been published (Rusko, 2018). This chapter focuses on underlying coopetition networks of tourism and specifically of tourism destinations. Because of the typical features of tourism destinations, multifaceted connections in competition and cooperation – and coopetition – are present in everyday business and activities among actors of the destination. These coopetitive relationships cover several levels, they are present in micro, meso, macro, and meta level interplay of tourism destination. Furthermore, the analysis shows that several studies about coopetitive networks in tourism destinations do not use terms “macro” or “meta” though these seem to be the main levels of the studies. This only reveals the fertile dimensions of coopetitive networks in tourism. These various relationships form coopetitive networks that represent several dimensions and levels of actors, competition, cooperation, and coopetition. This chapter introduces these multifaceted perspectives of coopetition networks, which have been described in the contemporary literature about tourism and tourism destination.

The purpose of this paper is to describe a technique for modeling transformer internal faults using transmission line modeling (TLM) method. In this technique, a model for simulating a two winding single phase transformer is modified to be suitable for simulating an internal fault in both windings.

TLM technique is mainly used for modeling transformer internal faults. This was first developed in early 1970s for modeling two‐dimensional field problems. Since, then, it has been extended to cover three dimensional problems and circuit simulations. This technique helps to solve integro‐differential equations of the analyzed circuit. TLM simulations of a single phase transformer are compared to a custom built transformer in laboratory environment.

It has been concluded from the real time studies that if an internal fault occurs on the primary or secondary winding, the primary current will increase a bit and secondary current does not change much. However, a very big circulating current flows in the shorted turns. This phenomenon requires a detailed modeling aspect in TLM simulations. Therefore, a detailed inductance calculation including leakages is included in the simulations. This is a very important point in testing and evaluating protective relays. Since, the remnant flux in the transformer core is unknown at the beginning of the TLM simulation, all TLM initial conditions are accepted as zero.

The modeling technique presented in this paper is based on a low frequency (up to a few kHz) model of the custom‐built transformer. A detailed capacitance model must be added to obtain a high‐frequency model of the transformer. A detailed arc model, aging problem of the windings will be applied to model with TLM + finite element method.

Using TLM technique for dynamical modeling of transformer internal faults is the main contribution. This is an extended version of an earlier referenced paper of the authors and includes inductance calculation, leakages calculation, and BH curve simulation while the referenced paper only includes piecewise linear inductance values. This modeling approach may help power engineers and power system experts understand the behavior of the transformer under internal faults.

The purpose of this paper is to report on the use of conjugate‐gradients (CG) as a means to accelerate the convergence of the iterative time‐reversal algorithm used for optimisation of electromagnetic devices.

The numerical time‐domain transmission line modelling method is used for time‐reversal optimisation. A comparison of the standard and CG time‐reversal is shown for two examples of microwave bandpass filter optimisation.

The paper demonstrates the time‐reversal optimisation that uses the CG matrix solver for perturbing the time reversal mirrors (TRM) fields.

The paper outlines the perturbation procedure of the CG time‐reversal and compares it to the standard time‐reversal optimisation. Two examples of microwave band pass filter optimisation have been considered and in each case it was demonstrated that CG time‐reversal significantly accelerates the optimisation process compared to the standard time‐reversal simulations.

The purpose of this study was to identify existing users' acceptance of the multidimensional health and fitness features of wrist-worn wearable devices (WWDs) required for each stage of physical activity (i.e. before, during and after) and examine the relationship between its acceptance (i.e. knowledge acquisition, perceived usefulness and perceived ease of use) and the actual use of its health and fitness attributes.

Both qualitative and quantitative approaches were taken to analyze the relationships. A focus group interview was conducted (N = 9) to design the research model, including the operationalized definition of the study constructs. A questionnaire survey was conducted with respondents in South Korea (N = 480). Partial least squares structural equation modeling via Smart PLS 3.0 was employed to test the hypotheses.

When users learned to use fitness functions and perceived them as useful for physical activity without causing any difficulty, they tended to use those functions more, which provided enhanced health benefits in the digitalized interactive environment of WWDs.

This research is one of the first to examine the relationship between the perceived user value of WWDs and their actual usage within a digitalized and interactive environment. The results are expected to offer theoretical insights into how well users accept the health and fitness components of WWDs. Practically, it will build awareness of what makes users adopt and use WWDs, helping practitioners design better health promotions and campaigns associated with WWDs.

The two‐dimensional discrete Huygens’ modelling or TLM simulation is presented for the TE electromagnetic field problems. The TLM element or node with variable traveling speed and characteristic impedance is applied to several practical problems including scattering at the edge of a wall and over periodic grids or grooves, wave propagation along a dielectric structure, and a mode coupling between two parallel optical waveguides. The TLM solutions are compared with the theoretical ones or the results of other numerical methods and reasonable agreement is achieved.